通过view实现rest api接口

Django rest framwork之view

基于Django的View实现Json数据的返回：

# _*_ encoding:utf-8 _*_
__author__ = 'LYQ'
__data__ = '2018/8/13 15:21'
import json

from django.views.generic.base import View
from django.http import HttpResponse,JsonResponse
from .models import *


class GoodsView(View):
    def get(self,request):
       good_list=Goods.objects.all()[:10]
       datas=[]
       # for good in good_list:
       #     json_dict = {}
       #     json_dict['name']=good.name
       #     json_dict['goods_desc']=good.goods_desc
       #     json_dict['category']=good.category.name
       #     json_dict['shop_price']=good.shop_price
       #     #时间不是json序列化的对象
       #     json_dict['time']=good.add_time
       #     datas.append(json_dict)
       #直接序列化
       from django.forms.models import model_to_dict
       #用来做序列化
       from django.core import serializers
       datas=[]
       for good in good_list:
           #image和datetime不能序列化
          data=model_to_dict(good)
          datas.append(data)
       datas=serializers.serialize('json',good_list)
       datas=json.loads(datas)
       # return HttpResponse(datas,content_type='application/json')
       return JsonResponse(datas,safe=False)

 Django rest framwork的简单介绍及安装（可参考官方网站）：

Django REST框架是用于构建Web API的强大而灵活的工具包。

您可能希望使用REST框架的一些原因：

• 该网站可浏览API是你的开发人员一个巨大的可用性胜利。
• 身份验证策略包括OAuth1a和OAuth2的程序包。
• 支持ORM和非ORM数据源的序列化。
• 可自定义 - 如果您不需要更强大的功能，只需使用常规的基于功能的视图。
• 丰富的文档和良好的社区支持。
• 受到国际知名公司的使用和信任，包括Mozilla，Red Hat，Heroku和Eventbrite。

要求

REST框架需要以下内容：

• Python（2.7,3.4,3.5,3.6,3.7）
• Django（1.11,2.0,2.1）

以下包是可选的：

• coreapi（1.32.0+） - 模式生成支持。
• Markdown（2.1.0+） - Markdown对可浏览API的支持。
• django-filter（1.0.1+） - 过滤支持。
• django-crispy-forms - 改进的HTML显示以进行过滤。
• django-guardian（1.1.1+） - 对象级权限支持。

安装

使用安装pip，包括您想要的任何可选包...

pip install djangorestframework
pip install markdown       # Markdown support for the browsable API.
pip install django-filter  # Filtering support

...或者从github克隆项目。

git clone git@github.com:encode/django-rest-framework.git

添加'rest_framework'到您的INSTALLED_APPS设置。

INSTALLED_APPS = (
    ...
    'rest_framework',
)

如果您打算使用可浏览的API，您可能还需要添加REST框架的登录和注销视图。将以下内容添加到根urls.py文件中。

urlpatterns = [
    ...
    url(r'^api-auth/', include('rest_framework.urls'))
]

请注意，URL路径可以是您想要的任何内容。

例

让我们看一个使用REST框架构建一个简单的模型支持的API的快速示例。

我们将创建一个读写API，用于访问有关项目用户的信息。

REST框架API的任何全局设置都保存在名为的单个配置字典中REST_FRAMEWORK。首先将以下内容添加到settings.py模块中：

REST_FRAMEWORK = {
    # Use Django's standard `django.contrib.auth` permissions,
    # or allow read-only access for unauthenticated users.
    'DEFAULT_PERMISSION_CLASSES': [
        'rest_framework.permissions.DjangoModelPermissionsOrAnonReadOnly'
    ]
}

别忘了确保你也加入rest_framework了INSTALLED_APPS。我们现在准备创建我们的API了。

注：如果出现utf8 decode的错误，把虚拟环境中的Libsite-packagespipcompat中的_init_.py的75行中的utf8改成gbk从新安装即可。

一.ApiView方式实现api

    1.serializers:

#form对应:Serializer,modelform:ModelSerializer
from rest_framework import serializers
from .models import *

class GoodsSerializer(serializers.Serializer):
    name = serializers.CharField(required=True,max_length=100)
    click_num = serializers.IntegerField(default=0)
    goods_front_image=serializers.ImageField()
    add_time=serializers.DateTimeField()

    def create(self, validated_data):
        return Goods.objects.create(**validated_data)

    2.views:    

from rest_framework.views import APIView
#状态码
from rest_framework import status 

from .models import *
from .serializers import GoodsSerializer
from rest_dramework.response import Reaponse


class GoodsListView(APIView):
    """
    List all snippets, or create a new snippet.
    """
    def get(self, request, format=None):
        goods = Goods.objects.all()
#many=True,goods是一个列表
        goods_serializer = GoodsSerializer(goods, many=True)
        return Response(goods_serializer.data)

    def post(self,request,format=None):
        serializer=GoodsSerializer(data=request.data)
#验证字段是否合法
        if serializer.is_valid():
           serializer.save()
           return Response(request.data,status=status.HTTP_201_CREATED)
        return Response(request.data,status=status.HTTP_400_BAD_REQUEST)

    3.ModelSerializer:

class GoodsSerializer(serializers.ModelSerializer):
    # 替换默认的category
    category = GoodsCategorySerializer()
    # 可能有多条many=True
    images = GoodsImageSerializer(many=True)

    class Meta:
        model = Goods
        # fields=('name','click_num','market_price','add_time','goods_front_image')
        # 外键为id,想要完整信息，嵌套Serializer
        fields = ('__all__')

二.GenericView方式实现api接口

from rest_framework import mixins
from rest_framework import generics
#基于mixins,必须重载get函数
 class GoodsListView(mixins.ListModelMixin,generics.GenericAPIView):
     """
     商品详情页
     """
     queryset = Goods.objects.all()[:10]
     serializer_class = GoodsSerializer
     #必须重写，不然默认无法接受get请求
     def get(self, request, *args, **kwargs):
         return self.list(request, *args, **kwargs)

三.Viewset和router实现api接口和配置

    1.viewset中的view：

    2.GenericViewset：

　　　　继承了ViewSetMixin和GenericAPIView,ViewSetMixin重写了as_view方法，initialize_request方法，initialize_request方法设置了很多action，在动态使用serializer时有很多的好处

class ViewSetMixin(object):
    """
    This is the magic.

    Overrides `.as_view()` so that it takes an `actions` keyword that performs
    the binding of HTTP methods to actions on the Resource.

    For example, to create a concrete view binding the 'GET' and 'POST' methods
    to the 'list' and 'create' actions...

    view = MyViewSet.as_view({'get': 'list', 'post': 'create'})
    """

    @classonlymethod
    def as_view(cls, actions=None, **initkwargs):
        """
        Because of the way class based views create a closure around the
        instantiated view, we need to totally reimplement `.as_view`,
        and slightly modify the view function that is created and returned.
        """
        # The suffix initkwarg is reserved for displaying the viewset type.
        # eg. 'List' or 'Instance'.
        cls.suffix = None

        # The detail initkwarg is reserved for introspecting the viewset type.
        cls.detail = None

        # Setting a basename allows a view to reverse its action urls. This
        # value is provided by the router through the initkwargs.
        cls.basename = None

        # actions must not be empty
        if not actions:
            raise TypeError("The `actions` argument must be provided when "
                            "calling `.as_view()` on a ViewSet. For example "
                            "`.as_view({'get': 'list'})`")

        # sanitize keyword arguments
        for key in initkwargs:
            if key in cls.http_method_names:
                raise TypeError("You tried to pass in the %s method name as a "
                                "keyword argument to %s(). Don't do that."
                                % (key, cls.__name__))
            if not hasattr(cls, key):
                raise TypeError("%s() received an invalid keyword %r" % (
                    cls.__name__, key))

        def view(request, *args, **kwargs):
            self = cls(**initkwargs)
            # We also store the mapping of request methods to actions,
            # so that we can later set the action attribute.
            # eg. `self.action = 'list'` on an incoming GET request.
            self.action_map = actions

            # Bind methods to actions
            # This is the bit that's different to a standard view
            for method, action in actions.items():
                handler = getattr(self, action)
                setattr(self, method, handler)

            if hasattr(self, 'get') and not hasattr(self, 'head'):
                self.head = self.get

            self.request = request
            self.args = args
            self.kwargs = kwargs

            # And continue as usual
            return self.dispatch(request, *args, **kwargs)

        # take name and docstring from class
        update_wrapper(view, cls, updated=())

        # and possible attributes set by decorators
        # like csrf_exempt from dispatch
        update_wrapper(view, cls.dispatch, assigned=())

        # We need to set these on the view function, so that breadcrumb
        # generation can pick out these bits of information from a
        # resolved URL.
        view.cls = cls
        view.initkwargs = initkwargs
        view.suffix = initkwargs.get('suffix', None)
        view.actions = actions
        return csrf_exempt(view)

    def initialize_request(self, request, *args, **kwargs):
        """
        Set the `.action` attribute on the view, depending on the request method.
        """
        request = super(ViewSetMixin, self).initialize_request(request, *args, **kwargs)
        method = request.method.lower()
        if method == 'options':
            # This is a special case as we always provide handling for the
            # options method in the base `View` class.
            # Unlike the other explicitly defined actions, 'metadata' is implicit.
            self.action = 'metadata'
        else:
            self.action = self.action_map.get(method)
        return request

    def reverse_action(self, url_name, *args, **kwargs):
        """
        Reverse the action for the given `url_name`.
        """
        url_name = '%s-%s' % (self.basename, url_name)
        kwargs.setdefault('request', self.request)

        return reverse(url_name, *args, **kwargs)

    @classmethod
    def get_extra_actions(cls):
        """
        Get the methods that are marked as an extra ViewSet `@action`.
        """
        return [method for _, method in getmembers(cls, _is_extra_action)]

    3.继承genericviewset的view写法：

　　　　　　GenericViewSet继承于GnericAPIView，没有重写get，post等方法，因此还需要继承mixin

class GoodsListViewSet(mixins.ListModelMixin,mixins.RetrieveModelMixin,viewsets.GenericViewSet):
    """
    商品详情页，分页，搜索，过滤，排序
    """
    #配置ip限制访问次数
    throttle_classes = (UserRateThrottle,AnonRateThrottle)
    queryset = Goods.objects.all()
    serializer_class = GoodsSerializer
    #分页
    pagination_class = GoodsPagination
    #配置认证类，防止公开网页（未登录可查看）不能访问
    # authentication_classes = (TokenAuthentication,)
    filter_backends=(DjangoFilterBackend,filters.SearchFilter,filters.OrderingFilter)
    #字段过滤(DjangoFilterBackend)
    # filter_fields = ('name', 'shop_price')
    filter_class=GoodsFilter
    #搜索过滤（rest_framework.filters.SearchFilter）
    search_fields = ('name','goods_brief','goods_desc')
    #排序过滤(rest_frameworkfilters.OrderingFilter)
    ordering_fields = ('sold_num', 'shop_price')

    def retrieve(self, request, *args, **kwargs):
        instance = self.get_object()
        instance.click_num+=1
        instance.save()
        serializer = self.get_serializer(instance)
        return Response(serializer.data)

　　　 　viewset和router配套使用：

　　　　　　第一种：配置url：

#在url.py文件中  
#配置GoodsListViewSet
 good_list=GoodsListViewSet.as_view({
#把get请求绑定到list方法上
         'get':'list',
     })
urlpatterns = [
#把good_list放入url中
 url('^goods/$',good_list,name='good_list'),
]  

　　　　    第二种：（使用router）

from rest_framework.routers import DefaultRouter

router = DefaultRouter()
# 配置goods的url
router.register(r'goods', GoodsListViewSet, base_name='goods')
#在调用router.urls时会自动把router中转换为url配置
urlpatterns = [
url('^', include(router.urls)),
]

四.View继承关系

    1.View继承关系(差异就是不同的mixin)：

 　　　　   GnericViewSet(drf)【比GnericAPIView继承增加了一个ViewSetMixin，在url中绑定了，router可以使用，还有实现了initialize_request方法设置了很多action方便不同serializer的使用】———>GnericAPIView(drf)【增加了筛选过滤分页，serializer等】———>APIView(drf)———>View(django)

    2.mixin：

　　CreateModelMixin

　　ListModelMixin

　　RetrieveModelMixin

　　UpdateModelMixin

　　DestroyModelMIxin

　　意境定制好了的view组合（继承GericAPIView不同的mixin实现不同的功能）：